Multiband subwavelength magnetic reflectors based on fractals

We use theory and experiment to demonstrate that a composite material, consisting of a metallic planar fractal and a metal sheet separated by a thin dielectric layer, can reflect electromagnetic wave in-phase at a series of frequencies, with some of the corresponding wavelengths much longer than the reflector’s own size. We show that the physics is governed by a series of intrinsic magnetic resonances and can be well described by an effective-media of frequency-dependent permeability.